Tapping into water supply from within the home?

Hi,

I am installing my own system and I'm wondering if I can tap into my water supply from within the home? The copper piping that stems up from my water supply and out to my outside faucet broke awhile back and a plumber had to come in and open up the wall to fix it. This wall happens to be right behind my switch enclosure where my water supply needs to tie in so I'd like to utilize the easy access to the water line from within the home. My design is as follows (I have fairly small areas to water):

Just outside the home I have a buried box where the water feed enters. Also within this box, I have four solenoid switches that lead to the front flower bed, front yard, back/side yard, and back/back yard. All piping converges at one of two "low points" with another solenoid switch at each of these low points so that I can bleed the lines.

I would like to tap into my water feed from within the home and run my tapped feed 5 feet to the buried box/switches. I would come through the wall (from inside the home to outside) and up a few feet to a PVB (mounted in an outside box on the wall), and then go back down the wall to the buried box where I tie into the system. I would also have a main shutoff valve downstream of the PVB (in between the PVB and the buried box).

Is this acceptable? Let me have it, but be gentle. This project started with a new rock wall around the flower bed that I intended to water with my battery operated timers. Then it grew and evolved and this is where I'm at now. Thanks!

This post has been edited 1 times, last edit by "stymon" (Apr 21st 2011, 5:31pm)

Water taps for irrigation usually do not tap into the supply from within the home so as to avoid noise and pressure losses.

Obviously if you tap into the water line from within your home, when ever the irrigation system is running, the water is going to be running through some of the plumbing within the home, and that can cause un-desired noise.

Second, water losses water pressure as it travels through a pipe. The smaller the pipe or the higher the flow, the greater the losses. Now if you have plenty of water pressure, this might not be an issue. If you have marginal water pressure, the additional losses of the water travelling from the meter to the house and back out again might be just enough to keep the system from running properly. Additionally, it can reduce water pressure in the house should you need water (such as a morning shower) while the irrigation system is running. Again, if you have plenty of pressure, that might not be an issue. But then there can be issues with water hammer depending upon the size of the pipe coming into the home. If you try to run an irrigation system through a long 3/4" copper water line, you can run into issues of too much water trying to flow through such a small pipe and cause water hammer when the valves close.

By tying into the water system just after the meter and using at least 1" pvc pipe, you reduce pressure losses cause by both the home and the irrigation system requiring water at the same time, you reduce the possibility of water hammer if your line from the meter to the home is only 3/4", and you avoid running water noises when the irrigation system is on.

Additionally, you are going to want a main shutoff valve BEFORE (upstream) of the PVB. There isn't much need for a shutoff after the PVB because you will not have a need to ever have water to the PVB without also having water to the irrigation system. By contrast, you will want to be able to shut water off to the PVB without shutting water to the house so that you can do repairs or maintenance on the PVB.